Blinding tool for drain tiles and the like



Feb. 22, 1966 v. A. KROHN 3,235,982

BLINDING TOOL FOR DRAIN TILES AND THE LIKE Filed April 16, 1963 2 Sheets-Sheet 1 INVEN TOR.

VZ'RNE A. KROHN AT TOR/VEYS Feb. 22, 1966 I v. A. KROHN 3,235,982

BLINDING TOOL FOR DRAIN TILES AND THE LIKE Filed April 16, 1963 2 Sheets-Sheet 2 FIG. 4

22/9 M2037 ll 30 /5 6 E65 VERIQ/E A. KIPOHN 7" TOFPNC Y5 United States Patent 3,235,982 BLINDING TOOL FOR DRAIN TILES AND THE LIKE Verne A. Krohn, 221 Hagge St., Worthington, Minn. Filed Apr. 16, 1963, Ser. No. 273,361 Claims. (Cl. 37-80) This invention relates generally to apparatus used in connection with the laying of drainage pipes or tiles, and more particularly, to attachments for trench digging machines used in tile laying, for the purpose of applying an initial covering of earth to tiles laid in a trench.

Drainage pipes or tiles, usually made from clay or the like, and placed in end-to-end relation in the bottom of a trench dug in the earth, are quite brittle and easily broken by stones or hard clods impinging thereon during the filling of the trench. Hence, it is common practice to initially cover or blind the newly laid tile by hand shoveling earth thereover, not only to hold the tiles in place, when the trench is filled by using power means such as a bulldozer or the like, but also to provide a protective covering over the tiles to prevent breakage thereof by large stones or large clods.

The primary object of this invention is the provision of a blinding tool, for attachment to a trench digging machine, which automatically banks and covers newly laid tile with a layer of earth, as the trench digging machine progresses over and through the ground, without displacement or injury to the tile.

Another object of this invention is the provision of a blinding tool which is quickly and easily mounted on conventional trench digging equipment, and which may be quickly and easily adjusted for use in trenches or ditches of various Widths.

Another object of this invention is the provision of a blinding tool having digging blades adapted to undercut opposite sides of a trench above the level of the tiles laid in the trench, whereby the earth falls gently to the opposite sides and top of the tile to cover the same.

Another object of this invention is the provision of a blinding tool as set forth having mounting means for the digging blades whereby the blades are automatically rendered inoperative when a predetenmined overload is applied to said blades, such as when large embedded rocks or the like are encountered by the blades.

Still another object of this invention is the provision of a blinding tool which is extremely simple and inexpensive to produce, which is highly efficient in operation, and which is rugged in construction and durable in use.

The above, and still further highly important objects and advantages of my invention will become apparent from the following detailed specification, appended claims and attached drawings.

Referring to the drawings, which illustrate the invention, and in which like reference characters indicate like parts throughout the several views:

FIG. 1 is a fragmentary View, partly in top plan and partly in horizontal section, illustrating the use of my blinding tool in covering drain tiles laid in a trench;

FIG. 2 is a vertical section taken substantially on the line 2-2 of FIG. 1;

FIG. 3 is an enlarged view in top plan of the blinding tool of my invention, some parts being removed and some parts being broken away and some parts being show-n in section;

FIG. -4 is a longitudinal section taken on the line 44 of FIG. 3; and

FIG. 5 is an enlarged fragmentary section taken substantially on the line 5-5 of FIG. 3.

Ditch or trench digging apparatus generally involves a mobile structure including a bucket equipped wheel or endless conveyor belt which extends downwardly into the ground and removes earth therefrom to form the ditch as the apparatus is moved continuously over the ground. Such apparatus is well known to those skilled in the art and, in and of itself, forms no part of the instant invention. Hence, for the sake of brevity, complete showing and description of a ditch or trench digging machine is omitted. It should sufiice to state that most ditch or trench digging machines developed for the purpose of laying drainage tile or pipe include a housing at the rear end thereof for supporting the side walls of the trench while the tile is laid at the bottom thereof. Such a housing is shown fragmentarily in FIGS. 1 and "2, the same being indicated in its entirety by the numeral 1 and includes a pair of laterally spaced vertical side walls 2 and 3 having stiffening members 4 and a cross bar or brace member 5 which supports the side walls 2 and 3 in laterally spaced relationship at the rear end thereof. As the ditching machine progresses, pipes or tiles, indicated at 6, are laid in end to end abutting relationship in the bottom of the trench, either by suitable mechanical means, not shown, or by an operator walking in the trench between the housing side walls 2 and 3. As above stated, after the tiles are laid, earth is manually shovelled thereon by a second operator, to blind or cover the tiles with a relatively thin layer of earth to hold the same in place during the trench filling operation. After blinding of the tiles, the trench is filled with the earth dug therefrom, using a powered shovel or bull dozer. During the filling operation, the layer of manually placed earth above the tile protects the same from large stones and the like which may be shoveled or pushed into the trench by the trench filling equipment.

The blinding tool of my invention comprises a frame structure 7 including a bar 8 that is elongated in the direction of movement of the frame structure 7, a rearwardly opening transverse hook element 9 at the front end of the bar 8 and preferably secured thereto by welding or the like, and an enlarged body 10 at the rear end of the bar 8. The body 10 comprises a pair of vertically spaced horizontal upper and lower platelike members 11 and 12 respectively, secured to the rear end of the bar 8 by nut equipped bolts or the like 13, and rearwardly diverging front walls 14 at opposite sides of the bar 8. The walls 14 are welded or otherwise rigidly secured to a desired one of the plate-like members 11 and 12. A vertical transverse rear wall element 15 is disposed at the central portion of the rear end of the plate like members 11 and 12, and is welded or otherwise rigidly secured to a desired one of said plate like members, to provide a stop element as will hereinafter be described.

A pair of generally rectangular mounting blocks 16 and 17 are pivotally mounted in the body 10 between the members 11 and 12, by means of nut-equipped bolts or the like 18, disposed on vertical axes adjacent the opposite sides of the body 10 at the rear end portion thereof. As shown particularly in FIG. 3, the mounting blocks 16 and 17 engage the rear wall element 15 to limit pivotal movements of the mounting blocks 16 and 17 in one direction. The mounting blocks 16 and 17 each define a pair of spaced parallel passages 19 and 20, the former of each of which slidably contain mounting arms 21 that extend transversely outwardly from opposite sides of the body 10 and which are, by virtue of their sliding engagement with their respective mounting blocks 16 and 17, transversely extensible and retractable from the body 10. The arms 21 are each provided with longitudinally spaced pockets or recesses 22 for selective reception of locking screws 23 having threaded engagement with nuts 24 Welded or otherwise rigidly secured to the mounting blocks 16 and 17. The screws 23 extending through suitable apertures in the blocks 16 and 17 to engage a selected on of the recesses 22. A pair of digging blades 25, having pointed front ends 26 and rearwardly diverging tail portions 27 are bolted or otherwise rigidly secured to the outer end portions of the mounting arms 21, the digging blades 25 being normally disposed in vertical planes which diverge forwardly in the direction of movement of the frame structure 7.

The trench wall undercutting or digging blades 25 are releasably locked in their operative positions shown in FIGS. 1 and 2 and by full lines in FIG. 3, by an abutment member 28 and a pair of latch elements 29. The abutment member 28 is centrally located in the body 10, and is mounted in a hollow mounting bracket 30, welded or otherwise rigidly secured to the bottom plate-like member 12. The abutment member 28 extends rearwardly outwardly from the bracket 30 and is adjustable forwardly and rearwardly relative to the body 10 by an adjustment screw or the like 31 screw threaded in the front end of the bracket 30. The abutment member 28 is releasably locked in any desired set position by means of a nutequipped locking screw 32 extending transversely through the abutment member 28 and through elongated slots 33 in opposite sides of the hollow bracket 30. At its rear end, the abutment member 28 is formed to provide forwardly diverging cam surfaces 34 that are normally engaged by cooperating cam surfaces 35 on the adjacent inner ends of the latch elements 29, see particularly FIGS. 3 and 4. The latch elements 29 are mounted for longitudinal sliding movements in the passages 20 of their respective mounting blocks 16 and 17, and are yieldingly urged toward engagement of their cam surfaces 35 with respective ones of the cam surfaces 34 of the abutment member 28, by coil compression springs 36 interposed between the outer ends of the latch members 29 and the slide blocks 37 slidably mounted in the passages 20 adjacent outer end walls 38, see FIG. 3. Yielding bias of the springs 36 is adjusted by means of adjustment screws 39 screw threaded through the end Walls 38 and engaging the slide blocks 37.

In operation, the frame structure 7 is hooked to the cross bar or brace of the trench digger housing 1 by means of the hook element 9, and lateral recesses are manually dug into the side wall of the trench for reception of the blades 25. Then, as the trench digging machine is moved forwardly to dig the trench, and the tiles 6 laid in the bottom thereof, the blinding tool is drawn forwardly by the trench digging machine to cause the blades 25 to undercut the side walls of the trench, as shown in FIGS. 1 and 2, thereby covering the tiles 6 with a loose fill of earth from the side walls of the trench. The working load imposed on the blades 25 is sufficient to maintain the blinding tool in a horizontal position behind the trench digging machine, said working load normally being insufficient to dislodge the cutting plates from their normal operative positions shown by full lines in FIG. 3. However, should one of the blades 25 encounter a heavy obstacle, such as a large stone or tree root, which would impose substantially more than the normal load on the blade, its corresponding latch element 29 will be cammed inwardly of its respective mounting block 16 or 17 against bias of its spring 36 to permit the respective mounting blocks 16 or 117 to pivotally move to swing the affected blade 25 toward an inoperative position shown by dotted lines in FIG. 3, in which inoperative position, the blade 25 is disposed inwardly of the adjacent trench side wall. It will be further noted, with reference to FIG. 3, that when the affected blade 25 and its mounting means is swung to its inoperative position, the latch element 29 thereof will engage the outer rear end portion of the adjacent front wall 14 to limit the swinging movement of the blade 25 toward its inoperative position. As soon as the obstruction is passed, the blade 25 may be manually swung to its operative position, and the blinding operation continued.

As shown in FIG. 2, the blinding tool is disposed but a short distance above the tile 6. Hence, any stones of smaller size in the trench side walls which may be dislodged by the blades 25 usually fall to the bottom of the trench alongside the tile. If any such stones should strike the tile, the distance traveled by the stones is not sufiicient to enable the same to gain suflicient momentum to injure the tiles. Once the tile has been blinded, as above described, earth may be dumped into the trench by a power shovel or bulldozer, the layer of blinding material over the tiles 6 cushioning the tiles against shock from falling earth and stones or hard clods which may be present in the fill mateial. With the use of my novel blinding tool, the blinding operation is automatic and a worker is released for other duties, or his services dispensed with altogether.

My invention has been thoroughly tested and found to be completely satisfactory for the accomplishment of the objectives set forth; and, while I have shown and described a commercial embodiment of my blinding tool, it will be understood that the same is capable of modification without departure from the spirit and scope of the invention, as defined in the claims.

What I claim is:

1. A tile binding tool comprising:

(a) an elongated rigid frame structure having front and rear ends,

(b) attaching means on the front end of said frame structure for attaching said frame structure to the rear end portion of a trench digging machine for trailing movements of said frame structure between the side walls of a trench made by said machine,

(c) a pair of blades normally disposed in vertical planes diverging in the general direction of said attaching means,

(d) a pair of rigid blade-carrying arms projecting laterally outwardly in opposite directions from the rear end portion of said frame structure and each of said arms having a different one of said blades rigidly secured to the outer end thereof,

(e) arm mounting means mounting said arms in said frame structure for extensible and retractable movements of said arms transversely of said frame structure to vary the distance between said blades,

(f) and a pair of releasable locking elements each operatively engaging a different one of said arms to rigidly lock said arms to said arm mounting means in desired adjusted positions thereof, whereby to maintain the lateral spacing therebetween.

2. The structure defined in claim 1 in which said arm-mounting means includes a pair of arm-mounting members pivotally secured to said frame structure for swinging movements on generally vertical axes when said frame structure is operatively connected to a trenchdigging machine to move said blades between normal operative trench side wall engageable positions and inoperative positions laterally inwardly spaced from said operative positions, and in further combination with means for releasably locking said arm-mounting members in their blade operative positions.

3. The structure defined in claim 2 in which said lastmentioned means include yielding connections between said arm-mounting members and said frame structure and yieldable responsive to rare-determined overload applied to their respective blades, during forward movement of said frame structure in a trench, to release the overloaded blade for movement thereof toward its inoperative position.

4. A tile binding tool comprising:

(a) an elongated frame structure having front and rear ends and including, a bar extending from the front end portion of said frame structure toward the rear end portion thereof, and an enlarged body at the rear end of said bar,

(b) a transverse rearwardly opening hook-like element at the front end of said bar adapted to engage the rear end portion of a trench-digging machine for trailing movements of said frame structure between the side walls of a trench made by said machine,

(c) a pair of laterally spaced blades normally disposed in vertical planes diverging in the general direction of said hook-like element,

(d) a pair of rigid blade-carrying arms having outer ends projecting laterally outwardly in opposite directions from said body and each having a different one of said blades rigidly attached to its outer end,

(e) arm mounting means including a pair of mounting members pivotally mounted in opposite side portions of said body an axes disposed generally vertically when said frame structure is attached to a trench-digging machine and each mounting a different one of said arms for extensible and retractable movements relative thereto, to vary the distance between said blades,

(f) releasable locking elements on said mounting members and engaging respective ones of said arms to rigidly lock said arms to their respective mounting members in desired adjusted positions thereof to maintain the lateral spacing between said blades,

g) stop means limiting pivotal movements of said mounting members in one direction of pivotal movement thereof,

(h) and releasable means normally limiting pivotal movement of said mounting members in the opposite direction of said pivotal movement thereof.

5. The structure defined in claim 4 in which said releasable means comprises an abutment member mounted in said body and a pair of latch elements one each mounted on a different one of said arm-mounting members, said latch elements having cam surfaces frictionally engaging cooperating surface portions of said abutment member, and yielding means urging said latch elements toward engagement with said abutment member to hold their respective arm-mounting members against said pivotal movements in said opposite direction and yieldable to permit said pivotal movement responsive to a predetermined overload applied to their respective blades during forward movement thereof through a trench.

References Cited by the Examiner UNITED STATES PATENTS 7/1952 Vaughn 37144 4/1957 Lindgren 172-269 X BENJAMIN HERSH, WILLIAM A. SMITH III,

Examiners. 

1. A TILE BINDING TOOL COMPRISING: (A) AN ELONGATED RIGID FRAME STRUCTURE HAVING FRONT AND REAR ENDS, (B) ATTACHING MEANS ON THE FRONT END OF SAID FRAME STRUCTURE FOR ATTACHING SAID FRAME STRUCTURE TO THE REAR END PORTION OF A TRENCH DIGGING MACHINE FOR TRAILING MOVEMENTS OF SAID FRAME STRUCTURE BETWEEN THE SIDE WALLS OF A TRENCH MADE BY SAID MACHINE, (C) A PAIR OF BLADES NORMALLY DISPOSED IN VERTICAL PLANES DIVERGING IN THE GENERAL DIRECTION OF SAID ATTACHING MEANS, (D) A PAIR OF RIGID BLADE-CARRYING ARMS PROJECTING LATERALLY OUTWARDLY IN OPPOSITE DIRECTIONS FROM THE REAR END PORTION OF SAID FRAME STRUCTURE AND EACH OF SAID ARMS HAVING A DIFFERENT ONE OF SAID BLADES RIGIDLY SECURED TO THE OUTER END THEREOF, (E) ARM MOUNTING MEANS MOUNTING SAID ARMS IN SAID FRAME STRUCTURE FOR EXTENSIBLE AND RETRACTABLE MOVEMENTS OF SAID ARMS TRANSVERSELY OF SAID FRAME STRUCTURE TO VARY THE DISTANCE BETWEEN SAID BLADES, (F) AND A PAIR OF RELEASABLE LOCKING ELEMENTS EACH OPERATIVELY ENGAGING A DIFFERENT ONE OF SAID ARMS TO RIGIDLY LOCK SAID ARMS TO SAID ARM MOUNTING MEANS IN DESIRED ADJUSTED POSITIONS THEREOF, WHEREBY TO MAINTAIN THE LATERAL SPACING THEREBETWEEN. 